著者

Masahiro KANAZAKI Kai TOMISAWA Koji FUJITA Akira OYAMA Hiroki NAGAI

出版者

The Japan Society of Mechanical Engineers

雑誌

Journal of Fluid Science and Technology (ISSN:18805558)

巻号頁・発行日

vol.14, no.3, pp.JFST0017, 2019 (Released:2019-12-19)

参考文献数

11

被引用文献数

2

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We redesigned the Mars Airplane Balloon Experiment Two (MABE-2) based on MABE-1 to improve the vehicle’s stability and controllability. Following the redesign, the MABE-2 vehicle had a larger horizontal tail volume than that of MABE-1 for improved stability performance. In addition, to further improve the stability and control characteristics, a rectangular planform was employed for the horizontal tail wing; in contrast, MABE-1 had a tapered planform. The vertical tail position of MABE-2 was moved to the end of the horizontal tail wing, because the vertical tail of MABE-1, which was positioned at the mid span of the horizontal tail wing, showed aerodynamic interaction with the horizontal tail wing. In this paper, we discussed the aerodynamic performance of a control surface based on computational fluid dynamics with variation in the deflection angle between the control surface and the horizontal tail (elevator), and we examined the effects of this redesign on longitudinal control characteristics. Numerical investigations confirmed the linear variation in the pitching moment and the aerodynamic force with the changing elevator deflection angle in MABE-2. Surface pressure observations indicated that MABE-2 shows a smooth variation in the pressure distribution with changing elevator deflection angle, while MABE-1 does not. These results demonstrate that the aerodynamic control characteristics of MABE-2 were improved in comparison to those of MABE-1.

著者

Hikaru AONO Katsutoshi KONDO Taku NONOMURA Masayuki ANYOJI Akira OYAMA Kozo FUJII Makoto YAMAMOTO

出版者

THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES

雑誌

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES (ISSN:05493811)

巻号頁・発行日

vol.63, no.1, pp.8-17, 2020 (Released:2020-01-04)

参考文献数

63

被引用文献数

7

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Aerodynamics of an owl-like wing model at low Reynolds numbers (Re = O(104–5)) are investigated using large-eddy simulations with high-resolution computational schemes. The airfoil shape of the owl-like wing model is constructed based on a cross-sectional geometry of the owl wing at 40% wingspan from the root. The chord-based Re ranges from 1.0 × 104 to 5.0 × 104 and the angle of attack (α) varies from 0 to 14 deg. The time-averaged lift (Cl) and drag coefficients computed are in reasonable agreement with the results of force measurement. The results computed clarify a nonlinear change in the Cl curve slope, which is due to an increase in the suction peaks in conjunction with the change in type of separation, the formation of a laminar separation bubble (LSB), and pressure recovery on the pressure side. The generation of the LSB on the suction and/or pressure sides at the Re of 2.3 × 104 and 4.6 × 104 are seen, while reattachments are observed only on the pressure side at the Re of 1.0 × 104 due to the camber of the wing. Furthermore, the owl-like wing model demonstrates favorable aerodynamic performance in terms of a maximum lift-to-drag ratio in comparison with several airfoils at the Re range considered. This is due to the strong suction peaks and distribution of surface pressure on the pressure side. It is emphasized that the concave lower surface enhances the time-averaged aerodynamic performance at all of the α even though the LSB is generated and fluctuation in lift history is induced at low α.

著者

Seiichiro MORIZAWA Taku NONOMURA Akira OYAMA Kozo FUJII Shigeru OBAYASHI

出版者

THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES

雑誌

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES (ISSN:05493811)

巻号頁・発行日

vol.61, no.6, pp.258-267, 2018 (Released:2018-11-04)

参考文献数

27

被引用文献数

8

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The effects of Mach number at Re = 3,000 for different airfoils (NACA0012, NACA0002, NACA4412, NACA4402) with thickness and camber geometries are investigated for the propeller blade design of a Mars airplane. The present study shows that thin and cambered airfoils have larger variations in Cl than symmetric airfoils. As for thin airfoils, Cl at higher α has rapid increases when the M∞ is low. This is because the flow separation occurs at the leading edge, and the flow is reattached on the airfoil surface. However, the rapid increase in Cl disappear as M∞ increases because the flow reattachment does not occurs. As for cambered airfoils, the decrease in Cl becomes larger than that on the symmetric airfoils when M∞ is higher. This is because Cp near the leading edge on the lower surface is smaller than that on the upper surface and the high-speed region on the lower side of the leading edge is enlarged as M∞ increases. Then, the Mcr at Re = 3,000 tends to be larger than that predicted by linear theory.